Motors to be installed in hybrid electric vehicles (HEVs: Hybrid Electric Vehicles) or electric vehicles (EVs: Electric Vehicles) require improved efficiency by, for example, effectively using magnet torque together with torque generated through the phenomenon of magnetic reluctance. Such motors widely use interior permanent magnet (IPM) design that varies such permanent magnets as neodymium magnets whose magnetic force is strong within the rotor structure.
With regard to motors of this kind, as seen from a motor described in JP 2013-38918A, called Patent Literature 1 below, it is proposed to equip the rotor with electromagnets having self-excitation type wound field function in view of the fact that permanent magnets with high magnetic force are expensive and difficult to get because a stable supply of magnetic material is hard to achieve. In the motor described in Patent Literature 1, an induction coil and an electromagnetic coil are individually formed around each of rotor salient structures with which magnetic flux generated by stator armature pole coils is directed to link in order to cause the rotor salient structure to function as an electromagnet by supplying rectified induced current to the electromagnetic coil after rectifying current induced by the induction coil.
In the motor described in this Patent Literature 1, torque applied to the rotor is improved by using reluctance torque that is generated by linking magnetic flux generated by stator armature pole coils with the rotor salient structures and magnet torque that is generated by causing the rotor salient structures to serve as electromagnets.